date-and-time

This library is a minimalist collection of functions for manipulating JS date and time. It's tiny, simple, easy to learn.

Why

JS modules nowadays are getting more huge and complex, and there are also many dependencies. Trying to keep each module simple and small is meaningful.

Features

• Minimalist. Approximately 2k. (minified and gzipped)
• Extensible. Plugin system support.
• Multi language support.
• Universal / Isomorphic. Works wherever.
• Older browser support. Even works on IE6. :)

Install

• via npm:

npm install date-and-time --save

• local:

<script src="/path/to/date-and-time.min.js"></script>

Recent Changes

• 0.14.1

  • Fixed a bug characters inside square brackets [] are not validated.

• 0.14.0

  • Feature Freeze

    We decided to freeze the feature with this version (except the following). The next will be 1.0.0.

  • To support ES Modules (without transpile) in the next version, the importing method has changed in the locale() and the plugin(). As this version you will see the warning message if using the old method. See LOCALE.md and PLUGINS.md for details.

  • Added transform() function to transform the format of a date string. When changing the format, previously you would convert the date string to a date object with the parse(), and then format it with the format() again, but you can now do this with a single function.

  // 3/8/2020 => 8/3/2020
  date.transform('3/8/2020', 'D/M/YYYY', 'M/D/YYYY');
  
  // previously
  const today = date.parse('3/8/2020', 'D/M/YYYY');
  date.format(today, 'M/D/YYYY');   // => '8/3/2020'

• 0.13.0

  • The format() now supports a compiled formatString.

  const pattern = date.compile('MMM D YYYY');
  
  date.format(new Date(2020, 2, 3), pattern); // => Mar 3 2020
  date.format(new Date(2020, 3, 4), pattern); // => Apr 4 2020
  date.format(new Date(2020, 4, 5), pattern); // => May 5 2020

  • The parse() now supports ... (ellipsis) token. The preparse() and the isValid() are too.

  // Cannot write like this even if you want to get only a date part.
  date.parse('Mar 05 2020 10:42:29 GMT-0800', 'MMM D YYYY');  // => Invalid Date
  
  // Previously, it was necessary to adjust the length of the format string by appending white spaces of the same length as a part to ignore.
  date.parse('Mar 05 2020 10:42:29 GMT-0800', 'MMM D YYYY                  ');
  
  // Can write simply like this using the ellipsis token.
  date.parse('Mar 05 2020 10:42:29 GMT-0800', 'MMM D YYYY...');

  • Added day-of-week plugin for the parser. However this is a dummy, not effective at all. See PLUGINS.md for details.

  // If a date string has day of week at the head, cannot parse it unless remove that part from it or fill white spaces that part of the format string.
  date.parse('Thu Mar 05 2020 10:42:29 GMT-0800', '    MMM D YYYY...');
  
  // This plugin provides `dd`, `ddd` and `dddd` tokens for such a case. However they are not effective at all because day of week has not information to identify a date.
  date.parse('Thu Mar 05 2020 10:42:29 GMT-0800', 'ddd MMM D YYYY...');

  • (Breaking Change) The subtract() now returns a REAL number. Previously, it returned values with truncated decimals.

  const now = new Date(2020, 2, 5, 1, 2, 3, 4);
  const new_years_day = new Date(2020, 0, 1);
  
  date.subtract(now, new_years_day).toDays(); // => 64.04309032407407

  • Added timespan plugin. This plugin provides timeSpan() function to display a formatted elapsed time. This will might be integrated with the subtract(). See PLUGINS.md for details.

  const now = new Date(2020, 2, 5, 1, 2, 3, 4);
  const new_years_day = new Date(2020, 0, 1);
  
  date.timeSpan(now, new_years_day).toDays('D HH:mm:ss.SSS'); // => '64 01:02:03.004'
  date.timeSpan(now, new_years_day).toHours('H [hours] m [minutes] s [seconds]');  // => '1537 hours 2 minutes 3 seconds'

  • Added microsecond plugin for the parser. Microsecond is not supported by date objects so that it is rounded millisecond at the inside. See PLUGINS.md for details.

Usage

• Node.js:

const date = require('date-and-time');

• With a transpiler:

import date from 'date-and-time';

• The browser:

window.date;    // global object

API

format(dateObj, formatString[, utc])

• Formatting a date.
  • @param {Date} dateObj - a Date object
  • @param {string|Array.<string>} arg - a format string or a compiled object
  • @param {boolean} [utc] - output as UTC
  • @returns {string} a formatted string

const now = new Date();
date.format(now, 'YYYY/MM/DD HH:mm:ss');    // => '2015/01/02 23:14:05'
date.format(now, 'ddd, MMM DD YYYY');       // => 'Fri, Jan 02 2015'
date.format(now, 'hh:mm A [GMT]Z');         // => '11:14 PM GMT-0800'
date.format(now, 'hh:mm A [GMT]Z', true);   // => '07:14 AM GMT+0000'

const pattern = date.compile('ddd, MMM DD YYYY');
date.format(now, pattern);                  // => 'Fri, Jan 02 2015'

Available tokens and their meanings are as follows:

You can also use the following tokens by importing plugins. See PLUGINS.md for details.

NOTE 1. Comments

String in parenthese [...] in the formatString will be ignored as comments:

date.format(new Date(), 'DD-[MM]-YYYY');    // => '02-MM-2015'
date.format(new Date(), '[DD-[MM]-YYYY]');  // => 'DD-[MM]-YYYY'

NOTE 2. Output as UTC

This function usually outputs a local date-time string. Set to true the utc option (the 3rd parameter) if you would like to get a UTC date-time string.

date.format(new Date(), 'hh:mm A [GMT]Z');          // => '11:14 PM GMT-0800'
date.format(new Date(), 'hh:mm A [GMT]Z', true);    // => '07:14 AM GMT+0000'

NOTE 3. More Tokens

You can also define your own tokens. See EXTEND.md for details.

parse(dateString, arg[, utc])

• Parsing a date string.
  • @param {string} dateString - a date string
  • @param {string|Array.<string>} arg - a format string or a compiled object
  • @param {boolean} [utc] - input as UTC
  • @returns {Date} a constructed date

date.parse('2015/01/02 23:14:05', 'YYYY/MM/DD HH:mm:ss');   // => Jan 2 2015 23:14:05 GMT-0800
date.parse('02-01-2015', 'DD-MM-YYYY');                     // => Jan 2 2015 00:00:00 GMT-0800
date.parse('11:14:05 PM', 'hh:mm:ss A');                    // => Jan 1 1970 23:14:05 GMT-0800
date.parse('11:14:05 PM', 'hh:mm:ss A', true);              // => Jan 1 1970 23:14:05 GMT+0000 (Jan 1 1970 15:14:05 GMT-0800)
date.parse('23:14:05 GMT+0900', 'HH:mm:ss [GMT]Z');         // => Jan 1 1970 23:14:05 GMT+0900 (Jan 1 1970 06:14:05 GMT-0800)
date.parse('Jam 1 2017', 'MMM D YYYY');                     // => Invalid Date
date.parse('Feb 29 2017', 'MMM D YYYY');                    // => Invalid Date

Available tokens and their meanings are as follows:

You can also use the following tokens by importing plugins. See PLUGINS.md for details.

NOTE 1. Invalid Date

If the function fails to parse, it will return Invalid Date. Notice that the Invalid Date is a Date object, not NaN or null. You can tell whether the Date object is invalid as follows:

const today = date.parse('Jam 1 2017', 'MMM D YYYY');

if (isNaN(today)) {
    // Failure
}

NOTE 2. Input as UTC

This function usually assumes the dateString is a local date-time. Set to true the utc option (the 3rd parameter) if it is a UTC date-time.

date.parse('11:14:05 PM', 'hh:mm:ss A');          // => Jan 1 1970 23:14:05 GMT-0800
date.parse('11:14:05 PM', 'hh:mm:ss A', true);    // => Jan 1 1970 23:14:05 GMT+0000 (Jan 1 1970 15:14:05 GMT-0800)

NOTE 3. Default Date Time

Default date is January 1, 1970, time is 00:00:00.000. Values not passed will be complemented with them:

date.parse('11:14:05 PM', 'hh:mm:ss A');    // => Jan 1 1970 23:14:05 GMT-0800
date.parse('Feb 2000', 'MMM YYYY');         // => Feb 1 2000 00:00:00 GMT-0800

NOTE 4. Max Date / Min Date

Parsable maximum date is December 31, 9999, minimum date is January 1, 0001.

date.parse('Dec 31 9999', 'MMM D YYYY');    // => Dec 31 9999 00:00:00 GMT-0800
date.parse('Dec 31 10000', 'MMM D YYYY');   // => Invalid Date

date.parse('Jan 1 0001', 'MMM D YYYY');     // => Jan 1 0001 00:00:00 GMT-0800
date.parse('Jan 1 0000', 'MMM D YYYY');     // => Invalid Date

NOTE 5. 12-hour notation and Meridiem

If use hh or h (12-hour) token, use together A (meridiem) token to get the right value.

date.parse('11:14:05', 'hh:mm:ss');         // => Jan 1 1970 11:14:05 GMT-0800
date.parse('11:14:05 PM', 'hh:mm:ss A');    // => Jan 1 1970 23:14:05 GMT-0800

NOTE 6. Token disablement

Use square brackets [] if a date-time string includes some token characters. Tokens inside square brackets in the formatString will be interpreted as normal characters:

date.parse('12 hours 34 minutes', 'HH hours mm minutes');       // => Invalid Date
date.parse('12 hours 34 minutes', 'HH [hours] mm [minutes]');   // => Jan 1 1970 12:34:00 GMT-0800

NOTE 7. Wildcard

A white space works as a wildcard token. This token is not interpret into anything. This means it can be ignored a specific variable string. For example, when you would like to ignore a time part from a date string, you can write as follows:

// This will be an error.
date.parse('2015/01/02 11:14:05', 'YYYY/MM/DD');            // => Invalid Date
// Adjust the length of the format string by appending white spaces of the same length as a part to ignore to the end of it.
date.parse('2015/01/02 11:14:05', 'YYYY/MM/DD         ');   // => Jan 2 2015 00:00:00 GMT-0800

NOTE 8. Ellipsis

The parser supports ... (ellipse) token. The above example can also be written like this:

date.parse('2015/01/02 11:14:05', 'YYYY/MM/DD...');   // => Jan 2 2015 00:00:00 GMT-0800

compile(formatString)

• Compiling a format string for the parser.
  • @param {string} formatString - a format string
  • @returns {Array.<string>} a compiled object

  const pattern = date.compile('MMM D YYYY h:m:s A');

  date.parse('Mar 22 2019 2:54:21 PM', pattern);
  date.parse('Jul 27 2019 4:15:24 AM', pattern);
  date.parse('Dec 25 2019 3:51:11 AM', pattern);

  date.format(new Date(), pattern); // => Mar 16 2020 6:24:56 PM

If you are going to call the format(), the parse() or the isValid() many times with one string format, recommended to precompile and reuse it for performance.

preparse(dateString, arg)

• Pre-parsing a date string.
  • @param {string} dateString - a date string
  • @param {string|Array.<string>} arg - a format string or a compiled object
  • @returns {Object} a date structure

This function takes exactly the same parameters with the parse(), but returns a date structure as follows unlike that:

date.preparse('Fri Jan 2015 02 23:14:05 GMT-0800', '    MMM YYYY DD HH:mm:ss [GMT]Z');

{
    Y: 2015,        // Year
    M: 1,           // Month
    D: 2,           // Day
    H: 23,          // 24-hour
    A: 0,           // Meridiem
    h: 0,           // 12-hour
    m: 14,          // Minute
    s: 5,           // Second
    S: 0,           // Millisecond
    Z: 480,         // Timsezone offset
    _index: 33,     // Pointer offset
    _length: 33,    // Length of the date string
    _match: 7       // Token matching count
}

This date structure provides a parsing result. You will be able to tell from it how the date string was parsed(, or why the parsing was failed).

isValid(arg1[, arg2])

• Validation.
  • @param {Object|string} arg1 - a date structure or a date string
  • @param {string|Array.<string>} [arg2] - a format string or a compiled object
  • @returns {boolean} whether the date string is a valid date

This function takes either exactly the same parameters with the parse() or a date structure which the preparse() returns, evaluates the validity of them.

date.isValid('2015/01/02 23:14:05', 'YYYY/MM/DD HH:mm:ss'); // => true
date.isValid('29-02-2015', 'DD-MM-YYYY');                   // => false

const result = date.preparse('2015/01/02 23:14:05', 'YYYY/MM/DD HH:mm:ss');
date.isValid(result);   // => true

transform(dateString, arg1, arg2[, utc])

• Transformation of date string.
  • @param {string} dateString - a date string
  • @param {string|Array.<string>} arg1 - the format string of the date string or the compiled object
  • @param {string|Array.<string>} arg2 - the transformed format string or the compiled object
  • @param {boolean} [utc] - output as UTC
  • @returns {string} a formatted string

This function transforms the format of a date string. The 2nd parameter, arg1, is the format string of it. Available token list is equal to the parse()'s. The 3rd parameter, arg2, is the transformed format string. Available token list is equal to the format()'s.

// 3/8/2020 => 8/3/2020
date.transform('3/8/2020', 'D/M/YYYY', 'M/D/YYYY');

// 13:05 => 01:05 PM
date.transform('13:05', 'HH:mm', 'hh:mm A');

addYears(dateObj, years)

• Adding years.
  • @param {Date} dateObj - a Date object
  • @param {number} years - number of years to add
  • @returns {Date} a date after adding the value

const now = new Date();
const next_year = date.addYears(now, 1);

addMonths(dateObj, months)

• Adding months.
  • @param {Date} dateObj - a Date object
  • @param {number} months - number of months to add
  • @returns {Date} a date after adding the value

const now = new Date();
const next_month = date.addMonths(now, 1);

addDays(dateObj, days)

• Adding days.
  • @param {Date} dateObj - a Date object
  • @param {number} days - number of days to add
  • @returns {Date} a date after adding the value

const now = new Date();
const yesterday = date.addDays(now, -1);

addHours(dateObj, hours)

• Adding hours.
  • @param {Date} dateObj - a Date object
  • @param {number} hours - number of hours to add
  • @returns {Date} a date after adding the value

const now = new Date();
const an_hour_ago = date.addHours(now, -1);

addMinutes(dateObj, minutes)

• Adding minutes.
  • @param {Date} dateObj - a Date object
  • @param {number} minutes - number of minutes to add
  • @returns {Date} a date after adding the value

const now = new Date();
const two_minutes_later = date.addMinutes(now, 2);

addSeconds(dateObj, seconds)

• Adding seconds.
  • @param {Date} dateObj - a Date object
  • @param {number} seconds - number of seconds to add
  • @returns {Date} a date after adding the value

const now = new Date();
const three_seconds_ago = date.addSeconds(now, -3);

addMilliseconds(dateObj, milliseconds)

• Adding milliseconds.
  • @param {Date} dateObj - a Date object
  • @param {number} milliseconds - number of milliseconds to add
  • @returns {Date} a date after adding the value

const now = new Date();
const a_millisecond_later = date.addMilliseconds(now, 1);

subtract(date1, date2)

• Subtracting.
  • @param {Date} date1 - a Date object
  • @param {Date} date2 - a Date object
  • @returns {Object} a result object subtracting date2 from date1

const today = new Date(2015, 0, 2);
const yesterday = new Date(2015, 0, 1);

date.subtract(today, yesterday).toDays();           // => 1 = today - yesterday
date.subtract(today, yesterday).toHours();          // => 24
date.subtract(today, yesterday).toMinutes();        // => 1440
date.subtract(today, yesterday).toSeconds();        // => 86400
date.subtract(today, yesterday).toMilliseconds();   // => 86400000

isLeapYear(y)

• Leap year.
  • @param {number} y - year
  • @returns {boolean} whether the year is a leap year

date.isLeapYear(2015);  // => false
date.isLeapYear(2012);  // => true

isSameDay(date1, date2)

• Comparison of two dates.
  • @param {Date} date1 - a Date object
  • @param {Date} date2 - a Date object
  • @returns {boolean} whether the dates are the same day (times are ignored)

const date1 = new Date(2017, 0, 2, 0);          // Jan 2 2017 00:00:00
const date2 = new Date(2017, 0, 2, 23, 59);     // Jan 2 2017 23:59:00
const date3 = new Date(2017, 0, 1, 23, 59);     // Jan 1 2017 23:59:00
date.isSameDay(date1, date2);   // => true
date.isSameDay(date1, date3);   // => false

locale([code[, locale]])

• Change locale or setting a new locale definition.
  • @param {string} [code] - language code
  • @param {Object} [locale] - locale definition
  • @returns {string} current language code

It returns a current language code if called without any parameters.

date.locale();  // => "en"

To switch to any other language, call it with a language code.

date.locale('es');  // Switch to Spanish

See LOCALE.md for details.

extend(extension)

• Locale extension.
  • @param {Object} extension - locale definition
  • @returns {void}

Extend a current locale. See EXTEND.md for details.

plugin(name[, extension])

• Plugin import or definition.
  • @param {string} name - plugin name
  • @param {Object} [extension] - locale definition
  • @returns {void}

Plugin is a named locale definition defined with the extend(). See PLUGINS.md for details.

Browser Support

Chrome, Firefox, Safari, Edge, and Internet Explorer 6+.

License

MIT